Electric-arc lamp.



all times the same current flowing the se the extremes of its travel, maybe.

.the one hand, would seem to be a desirable@ the cores in the solenoids. But a c oser analyrmx-1i n. Lixvis. or Baroness; Esens-naissl l rio'GENERAL'ELEettRiUfioMPANIY onnswii'oicii;

rsmzcmmcganeobmns; L

"sp'scificatisn gf 'Letterine-em.

To all `whom it may concern:

Beit 'kno wn'that I, FRANK MICHAEL LEwrs, a subject of the King of4 Great'Britain, and resident of Ireston'ville Terrace, Brighton, England, have invented certain new and use-v ful Improvements in Electric-Arc Lamps, of which the following is*.82*Specitication.- l l' The object 'of inyririv-if f tion isto use, in se ries wit'liea'cl'othe'r, 'more especially in a se*v rios circuit tapped across-'constant:potential mains nn electricarc lamp,v preferably of the inclosedjft ipe, which I have especially; l.def vised' for that purpose, which lamp dispenses. withthe shunt-regulating coil and=itsatte`nd,; ing expense-and 'inconvenience and in which laiiip' tlierefo're'- the entire arc-regulation is' efiect'c'd b" a'sris-regulat'ing"sodomy-jg In ""tl of the in losedarc t 4pe, Wh is actuate bym'4 series coil' a d c utch,.'theje'ediiigftakesV place in the tfi t two hours orso aft-er 'st'artingu the lam by the trave-'l5V of -the co're in theso enoid. ow assume that such a lamp were used-in a seriesl l' circuit ta edacross Aparallel mains, that is in a series circuit having anfapproximately constant potential impressed upon its ternu-l nals. the carbons burn away'and the arc lengthens, 'fthe Acurrent is lmomentarily :di-l minished and the core moves -down in itssolenoid. This? `allows the upper. carbon to move toward :the .lower carbon, and --thusjrestores the arc 4t'r,), 1 bot the. sameglength' and. *also restores the ,current to normal. yNow usuall; electriclam "is having series regulating coi aredesigne so that their. cores will work' at the position of maximum lpull, for-'a "v'en current in the solenoid. But. the ositioi of maximum pull on the :core is also t e position around about which there is `a variation of pull for agiven current for different positions. of the core.'l It follows then,under our as imptiom that practically the same current is :required to hold each 'core in position, no matter what that position, between."

'diriary lenig',

result, for it would seem to insure having at ries circuit, no matter what 'the itionsof sis shows that it is impossible to run such lamps in series on a constant potential-circui t and for this reason: If two or more such lamps be started, the ares-will naturally, by

lfthelonger arc. --But 'since-"asslrown a`b0v v'different relatiye' positions, zwithI corres ,ond

"the pu This on 'u accident if not otherwise, begin byzbeing'of* unequal len th. Sucha condition' being once establis ed, there" is no ade'f'iu'ate"re-" V storing force tending to shorten v'theunfduly longv arc or to lengthen the lunduly short farci.- It is true, of course,l that the position-ofthe core in the lamp having the shorter'iiirc dif f fers from' that of the corein the lamp havin lpractically.'the same amount of currentis r" -1 ulred to .hold -each of these'zeores'f-in tiferent. positions, these? cores will'irei'naij be no? adequate'force rought into play' tendto throw. two lcores'in'tot'he same relative n r eq'uilibrium in. these ositions. and4 therefwill .ing to hafvefas' it were,1 adi'erential action if" position- Havingfstarte'dwith vdifferent rell .-.atiye positions, the coreswillcontinuejin' ing different arc le ths, forth-"e resto j the travelin'the s'olenoi "i .-To make it possible towith `a"seriesvregulating coil Only, 'in series with otherlike Aamps 'on an vapproximately constant potential circuit,v I, 'in' accordance with my invention," so construct thelamp' that the amature ofthe-regulating magnet shall not, in its travel, 'b e ine uili-briiimin'its.

nlm 'an arc-lamp.

different positions for the .same current., Qn Y 'the contrary I have so `constr1'1cted it vthat for every different osition ofthe armature there-corresponds a iferent current s'treii th more slpecically, I so design the lamp'fthat l anced by the electromagnetic pull ot'thefgcoil .differs essentially for l ofthe armature which hasj to be'baL iiierentj positions of To sx ideas I win taks the me if t' imap, constructed in accordance with' my inven-` tion, inrwhich I employe series regulating solenoid only and a core having attached to ait avclutch, which core I here assume is i sucked upwardly to strike the arc.. I there upon so construct my lamp that it shall re -lquire considerabl. more current to holdl the core in position w en the core is in its liest positiomthat is afterthe arc has 11st en struck, thanis r uired Aafter the amp has l old the core in position '.moves down and down away from its highest position. ,i

We are now in a position to see what will happen if we use sa three lamps, 1, 2 and 3, 'each made in acco ance with my invention, in series, on a circuit mately constant potentialimpresse on its terminals. Consider the lamps after lthey havebeen burning for a short time and supose that lamp 2 has an arc-length about alf-way between the aro-lengths of lam s 1 and 3. The resistance of these arcs, ta en in' connection with the impressed volta e, will determine a certain current-How. is current flow will'manifestly correspond to the core-position of lamp 2. The core of lamp 1,.which we will assume to have the longer arc, will however be higher up, or-in a position nearer to thaty which it occupied when the arc was rst'struck. It will thereforerequire more current to hold itin equilibrium than that which is flowing. In conse uence, the core of lamp 1 will exercise an un alanced downward pressure suicient to throw it into the relative position of thefcore in lam 2, with suchmarginof errores I may initi determine.,` The core in lamp 3, which has the shortest a'rc, will be in a position below that of the core in lamp 2. In this position a less current than that which is actually iigwingwould hold' it in e uilibrium. This means that there is an unba anced' nward electromagnetic pull which, in accor ance with my invention, I make sufficient to raise the'core'in' lamp 3 to about the'4 .osition of the core lamp v2. It will thus e seen wh I designedIl-ylr construct the .lamps so that a iiferentequ` brating current corresponds to'eachdii'ferent core position, and so that the differential pulls exercised b these difl'ferent currents or the coresfshall e sufficient to bring back to its position a core which is out of its position by a distance larger than a given rmissible minimum. l

As have indicated. above, my invention 1s naturall applicable not only to -a lamp in which t e armatureor core is sucked u'p- ,wardly but also to. one -inwhich it is 'sucked 4downwardlyviylffthe' solenoid or electromagnetic coil.v at is moral may construct a lain embed ing my invention and havin the unction 1ere pointed out, in a variety o wa sand by means of avariety ofd'evices, eit 'ier electric al or mechanical." I shall however merely show one embodiment of' my in v'cntioii en'ipliasizing that my invention is not limited to the mero mechanical construction which I proceed to show, but-resides more generally in a group of lamps on a constant potential circuit cach lamp iavi'tl'ie characteristic which I have now soli Y y pointed out. L x

, In the ydrawings,flligure 1 is -a side elevation, partly-in section, showing a 'lamp 'embodying my invention after the arc has )ust having an a proxi- 'heavier the higher been struck; Fi 2 is a similar view showing the parts after the lamp has been burning for some time; and Fig. 3 is a diagrammatic view of three of these lamps in series across constant potentialmains. v

In the drawin s I have shown m lamp with a series regu ating coil 5 only. ,here 1s no'shunt coil.' The core 1 has ivotcd to it a clutch 6 which embraces a car on7 so that as the core is ulled up in the solenoid, the clutch tilts and) grips the carbon 7 and raises it tostrike the are. Fastened to the lamp frame is a pivot 50 upon which I mount a lever 2 connected, at one end, to-the core 1 by a link 8 and, at the 4other end, to a dash pot 9 for the dpurpose of 'steadyin the movement. y connected with t e lever 2 is an arm 3, atright angles tothe lever 2 carrying a weight 4,'the arm and weight constituting'a bo It will be seen that when the core 1 is in its highest position, after the arc has just been struck, the bob is to the right of the center-and exercises aforce tendin to deress the c ore. In effect the core is made eavier by the bob -in its highest position.

When the bob is vertical, it exercises no fo'ce'-4 upon the lever-2 and the core 1 exercises a downward pull determined b its weight and -that ofits attached parts. hen the-core is inits lower positions and the bob Vis to the left'of thevertical, as in F' 2,'it exercises a pressure tendin'gto raise t e core. This, in effect, makesthe downward pull of the -core less lthan that corresponding to. its we" ht In ot er and thatof its attached parts.

words theaction ofthebob, within the limits of the travel of the core, is to make the core v ulps it is drawn and lighter the lower down it fa This means that the higher thecore position,'the stronger the cur- -to-the u'piper core 'positions. More s ecificallystate rent in the solenoid necessary to hold tlie'core vinl Vthat position. Forevery position of the the dow'n- I ward mechanica pullof the core which ,has v to be balanced 'by the u ward electromagnet ic pull of the coil d' ers essentially-fordiflerent-positions of the core. AAs a result,

sponds to the current w iich is actually flowing, n. diferential force will be; called into i -'We' ferential force is made great enough to brin the.' (gore to its osition of equilibrium.

if the core is not in the osition which corremoments consi eration, however, will show that when my invention is embodied by adding a bob'to the lampbconstruction,l it -isnot necessary for this bo durin the travel of Vthe core, to be iir'stat one e and E then: at

the other side oithe vertical.

throughout the trv 1 of this" condition the i' .eciitei'vvhat' I'i'n'ay of lamp, namelytbj- 'gl yet Vstrongercurrent tio 'hold core in position, the nearer this Yis'fto'fthc the core, for even in. I;

sitionglust aftergst-rikiiig the arc'g'the di er? shown for obtaining the function which Ik have set forth or to have the c-urrent grow gradually stronger since the lamp may be arranged to have the currentngrow gradually weaker.

It is clear that in one of its broader aspects the bob which I emiloy is a device which varies the mechanical pull exerted by the armaturel or core itself, which pull must of course be balanced by the electromagnetic pull ofthe solenoid. I may therefore, for convenience, use the phrase mechanical pullvarying device to include all devices which act to vary the mechanical pull of the armature in its different positions. And, when I speak of varying the pull, I mean of course that the.

variation of pull for the dilierent positions shall be suicient to vbring into play the differential restoring force u on that armature which happens to be out o position.

For the purpose of insuring additional reliability in synchronisni,` I preferto employ a regulation-restarter, which I roceed to describe. rlhe lever 2 is extende to the left in a prolongation 10, carrying a pin 15, Working m a slotted link 16, attached tothe keeper 13, of an electromagnet 14, in the lamp circuit. The slot in the link is of suficient length for a certain amount of regulation of the arc by means of the regulating solenoid 5, to take place, without arly movementof the keeper, the pin 15 playing between the extremities ofthe slot 16 during such regulation.

Let us assume thatthe parts are in the position which they occupy when no current 1s on, that is to say wit the carbons together, the clutches resting on their stops,- the lever 2 lying inclined with the core well below the solenoid and the keeper hanging above the electromagnet with the pin at the top of the slot. When the current is now switched on, it traverses the pair of carbons, the solenoid 5 and the electromagnet 141 The core is pulled upwards, its end of the up am the are is struck. the other end of the rocking lever is depressed, thc keeper 13 Vis 'brought within c5 pulling distance of the electromagnet 14 and The bob readilyl stay at one side ol' the vertical? rockin" lever is raised, the clutch is pulled I At the same timeA jis attracted and held by the latter. `distance through which the keeperinioves is howeveremailen than the?? distance niovesmsof ,that the pinidescendsnsomelfdisf tancein.the?slot=andthefkeepernoflonger` .lian sffrointts-limbinifthe levens@ magnet and ,theaa' innsgoesfsorrmntalt" has ,reach'edfthe headset the slotwhen'ithe corecan drop no further but remains sta.- tionary The carbon cannot now-feed and the are gets longer until it breaks. The

solenoid and 'eleetromagnet are 'nowY no, Y

longer traversed by the current, so that both core and kee er are released, the former dro ping and ringing the clutch in Contact wi'tli the stop so that the upper carbon dro s into contact with the'lower carbon. T e circuit is now restablished and the cycle of operations takes place as before.

. It will be seen that so long as the parts are in such positions that the pin is free within the slot a certain amount of re lation may take place, hut that the car ons cannot be released so as to come-in contact until the keeper is released from its electromagnet. l

The process disclosed herein is claimed in my copending application Serial No. 41 1,679, iiled January 2 0, 1908, as a division hereof.

I claim,

1. A constant-potential series circuit including arc-lan'ipa each comprising a series regulating coil only7 and a coacting armature equilibrated in its several positions by current strengths which differ sufficiently in value that a differential'restoring force is exerted upon any armature of the series which may be out of positionJ substantially as described.

2. A constant-potential series circuit including arc-lamps,eaeh comprising a series regulating coil only, and a coacting armature exerting a variable mechanical pull differing sufficienti in its several positions to generate a di erential restoring force upon any armature of the group which may be out of position, substantially as described.

3. A constant-potential series circuit including arc-lamps, each comprising a series regulating coil only, a coacting armature, and a mechanical pull-varying device cooperating 'with the armature, whereby a differential restoring -force is exerted upon any armature of the group which may be out of positionsubstantially as described.

' 4e. A `co1stantpotential series circuit including arc-lamps, each comprising a series regulating coil only,l a coacting armature, and a pivoted bob cooperating with the armature for exercising a differential re- :storinglforce upon such armature of the l which may be out of position, and a. re la group as happens to be out of position, sub' tion`restarter, substantial?l as describe stantially as described. In testimony whereof have signed my 5. A constant-potential series circuit nneme to this specification in the presence of 5 cluding arc-lamps, each comprising s. series two witnesses.

regulating coil only, a. coacting armature equilabrated in its several positions by current strengths w 'ch differ sucently in Witnesses: value that a differential restoring force is PERCY W. SMITH, y 10 exerted upon any armature of the series KARL VossLoH.

FRANK M. LEWIS. 

